Multiple-gun cathode-ray tube beam magnet assembly



R. A. MAHER April 23, 1957 MULTIPLE-GUN CATHODE-RAY TUBE BEAM MAGNETASSEMBLY Filed Sept. 1. 1955 mvmroz; RICHARD A. MA HER. -azdm QWATTORNEY3.

MULTIPLE-GUN CATHODE-RAY TUBE BEAM 1 MAGNET ASSEMBLY Richard A. Maher,Cincinnati, Ohio, assignor to Avco Manufacturing Corporation,Cincinnati, Ohio, a corporation of Delaware Application September 1,1953, Serial No. 377,935 2 Claims. or. 317-200 This invention relatesgenerally to cathode-ray tube deflecting means and more specifically toa means which provides a fixed field, adjustable in space, for use indeflecting and positioning individual electron beams in a multiple-guncathode-ray tube.

With the advent of color television and the use of cathode-ray tubeshaving a multiple-gun structure, it became necessary to providestructures for adjusting the spatial position of the individual electronbeams relative to the remaining beams emanating from the multiplegununit. The bending effect of a permanent magnet field on the electronbeam being well known, it became conventional to position magnets aroundthe neck of the tube.

These prior art adjustable magnet mount structures were fixedly attachedto the receiver chassis and arranged to allow positioning of the variousmagnets relative to the electron beam desired to be brought undercontrol. Though these devices have proved to be relatively satisfactoryin laboratory units where the etfect of a shift between the cathode-raytube and the receiver chassis can be readily corrected, it would bedesirable to provide a magnet assembly fixedly mounted on thecathode-ray tube so that movement of the cathode-ray tube relative tothe receiver chassis cannot change the magnetic force exerted by eachmagnet on the electron beams.

Further, it would be desirable to provide magnet mounts which wereeasily adjustable and also capable of being locked or rigidly fixed inposition. Thus, it is an object of this invention to provide a beampositioning magnet mount which is fixedly attached to the neck of thecathode-ray tube.

It is also an object of this invention to provide a magnet mount havinga wide range of magnet positioning adjustments.

It is a further object of this invention to provide a magnet positioningassembly which, though easily adjustable, can be locked or secured in aselected position.

Briefly, my invention comprises a magnet mount fabricated fromnon-magnetic material and provided with a plurality of flange portions,each of which is arranged to hold an adjustable magnet positioningassembly. Each adjustable magnet positioning assembly comprises a studthreaded on the outside surface to receive a knurled nut which, togetherwith the stud, forms a socket into which a centrally threaded ballmember is positioned. A rubber or fiber washer is used to introducevariable frictional contact between the knurled nut and the ballsupporting stud in order that the ball may be rotated in its socketwithout loosening the knurled nut. A magnet rod is threaded on one endto fit into the threaded opening in the ball member and is also threadedat the opposite end to receive and support a magnet-carrying block orsimilar holding device. Each magnet-carrying block carries a smallpermanent magnet having sutficient strength to influence the electronbeams desired to be controlled.

For a better understanding of the present invention, together with otherand further objects, advantages and capabilities thereof, reference ismade to the following disclosure and appended claims in connection withthe accompanying drawings in which:

Fig. 1 is a drawing showing an assembly of a specific embodiment of myinvention; and

Fig. 2 is a cross-section of the ball and socket magnet 1 arm adjustingassembly.

In Fig. 1, I have shown a non-magnetic mounting ring 11 having outwardlyextending flange supporting portions 12, each of which is integrallyconnected to a flange element 13. Each flange 13 supports a magnetpositioning .assembly 14 having a stud 15 threaded on its outsidesurface to receive internally threaded knurled nut 16. Stud 15, as bestshown in Fig. 2, may be attached to flange 13 by spinning, welding orany other method resulting in an integral connection.

Ball member 17 is positioned between knurled nut 16 and the uppersurface of stud 15 which may be either recessed to receive the lowersurface of ball 17 or, as shown in Fig. 2, drilled to provide arelatively small contacting shoulder. j

'A washer 9 fabricated from plastic, rubber, fiber, or some othersimilarly resilient material is provided for stud 15. This washer musthave suflicient thickness to engage the lower surface of knurled nut 16before the nut is advanced on the stud suiiiciently to lock ball 17 inthe resulting socket.

Each magnet rod 18 is integrally connected to a ball 17 in conventionalmanner, such as in Fig. 2, where ball 17 is shown internally threaded toreceive the threaded lower end of the magnet rod. It will be apparentthat this structure allows magnet rod 18 to be moved into any angularposition by loosening nut 16 until ball 17 is free to turn in the socketformed by stud 15 and the under portion of knurled nut 16 within thelimits imposed by the shoulder on knurled nut 16. Washer 9 holds knurlednut 16 in position relative to stud 15. After rod 18 has been broughtinto the desired angular position, knurled nut 16 may be tightened so asto frictionally lock ball 17 between the upper shoulder on stud 15 andthe portion of knurled nut 16 hearing against the upper surface of ball17.

Each magnet rod 18 is threaded to receive an internally threaded magnetblock 22 which carries a cylindrical magnet 21 having sufiicient fieldstrength to act on a magnetic beam directed through ring 11. Since eachmagnet21 is positioned along one of the sides of its carrying block, andsince the threaded opening in the magnet block is in spaced relationshipwith the position of the magnet, rotation of the magnet block around thelongitudinal axis of the magnet rod results in movement of theparticular magnet in question along an eccentric path.

Except for magnets 21, the complete structure is fabricated fromnon-magnetic material. Non-conducting bolt 30, which may be plastic, isused to close magnet supporting ring 11 in order to make certain thatthe ring does not form a large energy-consuming shorted turn around thelongitudinal axes of the electron beams being controlled. In otherwords, the gap left in the ring by bolt 3 0 keflps eddy currents fromcirculating completely around ring This magnet assembly has theadvantage over the prior art of being readily adjustable along thelongitudinal axis of the cathode-ray tube neck and of being immune tovibratory movements of the cathode-ray tube relative to the receiverchassis. In addition, each magnet is adjustable through a wide range ofpositions, and the magnets 3 may be locked or secured in any position bytightening knurled nut 16.

Further, magnet blocks 22, which may be fabricated from suitable plasticor fiber, provide a wide range of positions available on the magnetsupporting rod for fine adjustments after the rod is locked into place.

While there has been shown and described what is at present consideredthe preferred embodiment of the present inventiomit will be obvious tothose skilled in the art that various changes and modifications may bemade therein without departing from the invention as defined by theappended claims.

Having thus described my invention, I clairn:

l. A permanent magnet mount assembly for aesthetic: ray tube comprisingagenerally circular mounting ring,

symmetrically'spaced outwardly extending flange portionsfixedly attachedtovsaid ring, a permanent magnet for each flange, a-separate supportblock for each magnet, formed to hold the magnet and to provide athreaded aperture in spaced" relationship with and normal to thesupported magnet, a'support rod for each block threaded to support theassociated block so as to allow rotation of the block around and alongthe longitudinal axis of the rod, each magnet being so mounted as to beoffset from the associated support rod, and a ball and socket joint forfixing saidrod with respect to said mounting ring and providingarticulation between each of said flanges and theassociatedmagnet-supporting rod, the ball'being se; cured to the end ofthe rod remote from the block and the socket being secured to theflange, all of the above memhere beingofnon-magnetic material exceptingthe permanent magnets.

2. A permanent magnet mount assembly for a cathoderay tube comprisingthe combination of a generally circular mounting ring formed to providea plurality of symmetrically spaced outwardly extending flange portions,

one for each magnet to be supported, a threaded stud secured on andextending normally to each flange, a

knurled nut shaped to form a socket with each stud,

associated magnet support rod, each magnet being so' mounted as to belaterally displaced from its associated support rod, all elements ofsaid combination other than the permanent magnets being of non-magneticmaterial.

References Cited in the file of this patent UNITED STATES PATENTS KabussApr. 1, 1952 Ingle June V2, 1953

